Multi-layered information recording medium, recording apparatus, and recording method

ABSTRACT

A multi-layered information recording medium including a plurality of recording layers, the multi-layered information recording medium comprising: a user data area for recording user data; and a plurality of spare areas including at least one replacement region, wherein when the user data area includes at least one defect region, the at least one replacement region may be used in place of the at least one defect region, wherein a first spare area of the plurality of spare areas is positioned so as to be contiguous to a first user data area of a first recording layer, a second spare area of the plurality of spare areas is positioned so as to be contiguous to a second user data area of a second recording layer, and the first spare area and the second spare area are positioned approximately at the same radial position on the multi-layered information recording medium.

This application is a continuation application of U.S. patentapplication Ser. No. 11/566,717 filed on Dec. 5, 2006, which claimspriority to U.S. application Ser. No. 10/338,430 filed Jan. 8, 2003, nowU.S. Pat. No. 7,184,377 issued Feb. 27, 2007, the entire disclosures ofwhich are incorporated herein by reference, and is related to co-pendingsibling U.S. applications, Attorney Docket No. OKUDP0181USB (U.S.application Ser. No. ______), OKUDP0181USC (U.S. application Ser. No.______), OKUDP0181USE (U.S. application Ser. No. ______) andOKUDP0181USF (U.S. application Ser. No. ______), all filed on May 14,2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-layered information recordingmedium including at least two recording layers, a recording apparatusfor use with the multi-layered information recording medium, and arecording method for recording information in the multi-layeredinformation recording medium.

2. Description of the Related Art

A typical information recording medium which has a sector structure isan optical disc. In recent years, AV data, such as audio data, videodata, and the like, has been digitalized, and accordingly, an opticaldisc having a higher recording density and larger capacity has beendemanded. Providing a plurality of recording layers is useful inincreasing the capacity of a disc. For example, the capacity of aread-only DVD has been increased about two times by providing tworecording layers to the DVD.

FIG. 1 shows a structure of a typical optical disc medium 1 including atrack 2 and sectors 3. The optical disc medium 1 includes a track 2turned multiple times in a spiral arrangement. The track 2 is dividedinto a large number of small sectors 3. Regions formed on the discmedium 1 are roughly classified into a lead-in zone 4, a user data area8 and a lead-out zone 6. Recording or reproduction of user data isperformed on the user data area 8. The lead-in zone 4 and the lead-outzone 6 are provided as margins such that an optical head (not shown) canappropriately follow a track even if overrunning of the optical headoccurs when the optical head accesses an end portion of the user dataarea 8. The lead-in zone 4 includes a disc information zone which storesparameters necessary for accessing the disc medium 1. Physical sectornumbers (hereinafter, abbreviated as “PSN(s)”) are assigned to thesectors 3 in order to identify the respective sectors 3. Further,consecutive logical sector numbers (hereinafter, abbreviated as“LSN(s)”) which start with zero are assigned to the sectors 3 such thata superior apparatus (not shown) such as a host computer identifies therespective sectors 3.

FIG. 2 illustrates a principle of reproduction of data from a read-onlyoptical disc 30 having two recording layers. Herein, production of theread-only optical disc 30 of FIG. 2 is briefly described. In the firstplace, grooves are formed on substrates 31 and 32 so as to form spiraltracks. Over the grooved surfaces of the substrates 31 and 32, recordinglayers 33 and 34 are attached so as to cover the grooved surfaces. Thesubstrates 31 and 32 are combined so as to sandwich transparentlight-curable resin 35 between the recording layers 33 and 34, therebyobtaining a single read-only optical disc 30. In this specification, forconvenience of description, in FIG. 2, a recording layer 34 closer tothe incoming laser light 38 is referred to as a first recording layer34; whereas the other recording layer 33 is referred to as a secondrecording layer 33. The thickness and composition of the first recordinglayer 34 are calibrated such that the first recording layer 34 reflectsa half of the incoming laser light 38 and transmits the other half ofthe incoming laser light 38. The thickness and composition of the secondrecording layer 33 are calibrated such that the second recording layer33 reflects all of the incoming laser light 38. An objective lens 37forgathering the laser light 38 is moved toward or away from the opticaldisc 30 such that the convergence point (beam spot) 36 of the laserlight 38 is placed on the first recording layer 34 or the secondrecording layer 33.

FIGS. 3A, 3B, 3C and 3D show tracks of two recording layers 41 and 42 ofa read-only DVD, which are called parallel paths, and the reproductiondirection and sector numbers. FIG. 3A shows a spiral groove pattern ofthe second recording layer 42. FIG. 3B shows a spiral groove pattern ofthe first recording layer 41. FIG. 3C shows the reproduction directionin user data areas 8 provided on the recording layers 41 and 42. FIG. 3Dshows sector numbers assigned to the recording layers 41 and 42.

Now, consider the read-only DVD disc is rotated clockwise when it isviewed from the back face side of the disc in the direction along whichlaser light comes onto the disc, i.e., when it is viewed from the backside of the sheets of FIGS. 3A and 3B. In this case, the laser lightmoves along the track 2 from the inner circumference side to the outercircumference side of the recording layers 41 and 42. In the case whereuser data is sequentially reproduced along the reproduction directionshown in FIG. 3C, reproduction is first performed from the innermostcircumference position to the outermost circumference position of theuser data area 8 of the first recording layer 41. Then, reproduction isperformed from the innermost circumference position to the outermostcircumference position of the user data area 8 of the second recordinglayer 42. The user data areas 8 of the first and second recording layers41 and 42 are sandwiched by the lead-in zone 4 and the lead-out zone 6such that an optical head can appropriately follow the track 2 even ifoverrunning of the optical head occurs. As shown in FIG. 3D, the PSNsand LSNs of each of the recording layers 41 and 42 are incrementallyassigned along the reproduction direction. The PSNs do not necessarilyneed to start with zero in view of convenience of disc formation.Further, the PSNs do not necessarily need to be continuously assignedbetween the first and second recording layers 41 and 42 (for example, avalue corresponding to the layer number may be provided at the firstposition of each sector number). As LSNs, consecutive numbers whichstart with zero are assigned to all of the user data areas 8 included inthe optical disc. That is, in the user data area 8 of the firstrecording layer 41, the LSN at the innermost circumference position iszero, and incrementally increases toward the outermost circumference.The LSN at the innermost circumference position of the user data area 8of the second recording layer 42 is a number obtained by adding 1 to themaximum LSN of the first recording layer 41. The LSN of the secondrecording layer 42 also increases in an incremental manner toward theoutermost circumference.

FIGS. 4A, 4B, 4C and 4D show tracks of two recording layers 43 and 44 ofa read-only DVD, which is called an opposite path arrangement, and thereproduction direction and sector numbers. FIG. 4A shows a spiral groovepattern of the second recording layer 44. FIG. 4B shows a spiral groovepattern of the first recording layer 43. FIG. 4C shows the reproductiondirection in user data areas 8 provided on the recording layers 43 and44. FIG. 4D shows sector numbers assigned to the recording layers 43 and44.

Now, consider the read-only DVD disc is rotated clockwise when it isviewed from the back face side of the disc in the direction along whichlaser light comes onto the disc, i.e., when it is viewed from the backside of the sheets of FIGS. 4A and 4B. In this case, the laser lightmoves along the track 2 from the inner circumference side to the outercircumference side in the first recording layer 43, but from the outercircumference side to the inner circumference side in the secondrecording layer 44. In the case where user data is sequentiallyreproduced along the reproduction direction shown in FIG. 4C,reproduction is first performed from the innermost circumferenceposition to the outermost circumference position of the user data area 8of the first recording layer 43. Then, reproduction is performed fromthe outermost circumference position to the innermost circumferenceposition of the user data area 8 of the second recording layer 44. Theuser data area 8 of the first recording layer 43 is sandwiched by thelead-in zone 4 and a middle zone 7 such that an optical head canappropriately follow the track 2 even if overrunning of the optical headoccurs. The user data area 8 of the second recording layer 44 issandwiched by the middle zone 7 and the lead-out zone 6. The function ofthe middle zone 7 is the same as that of the lead-out zone 6. As shownin FIG. 4D, the PSNs and LSNs of each of the recording layers 43 and 44are incrementally assigned along the reproduction direction as in theabove-described parallel paths, except that the relationship between thesector numbers and the radial direction because the spiral direction ofthe track 2 of the second recording layer 44 is inverse to the spiraldirection of the track 2 of the first recording layer 43. In the userdata area 8 of the first recording layer 43, the LSN is zero at theinnermost circumference position, and increases incrementally toward theouter circumference side. The LSN at the outermost circumferenceposition in the user data area 8 of the second recording layer 44 is anumber obtained by adding 1 to the maximum LSN in the user data area 8of the first recording layer 43, and increases in an incremental mannertoward the innermost circumference.

Above, read-only optical discs have been described. Now, featuresspecific to a rewritable optical disc are described. Such featuresresult from the fact that requirements on a margin for a recordingoperation are more severe than that for a reproduction operation.

FIG. 5 shows a region layout of the recording layer 45 included in aDVD-RAM which is a rewritable DVD disc. The DVD-RAM has only onerecording layer (i.e., recording layer 45). As shown in FIG. 5, thelead-in zone 4 of the recording layer 45 includes a disc informationzone 10, an OPC (Optimum Power Calibration) region 11, and a defectmanagement region 12. The lead-out zone 6 includes another defectmanagement region 12. Spare areas 13 are provided between the lead-inregion 4 and the user data area 8, and between the user data area 8 andthe lead-out zone 6, respectively.

The disc information zone 10 stores disc information regardingparameters necessary for recording/reproduction of data of the opticaldisc or data format of the optical disc. The disc information zone 10 isalso included in a read-only optical disc, but the disc information zone10 of the read-only optical disc includes nothing important other than aformat identifier used for identifying the optical disc. On the otherhand, in a rewritable optical disc, specific recommended values for thecharacteristics of the laser light used for recording, such as the laserpower, pulse width, and the like, are stored for each generated markwidth. The disc information zone 10 is a read-only region in whichinformation is typically written in at the time of production of thedisc. In a DVD-RAM, pits are formed in the disc surface as in a DVD-ROM.(There is a recording principle different from such a “pit” recordingprinciple. For example, in a CD-RW, information is superposed on ameander region (called a “wobble” region) of a groove.)

The OPC region 11 is provided for optimally calibrating the recordingpower of laser light. A disc manufacturer stores recommended laserparameters for a recording operation in the disc information zone 10.However, a laser element used by the disc manufacturer for obtaining therecommended values is different from a laser element incorporated in anoptical disc drive apparatus, in respect to laser characteristics, suchas the wavelength, the rising time of the laser power, and the like.Further, even a laser element of the same optical disc drive, the lasercharacteristics thereof vary because of a variation of the ambienttemperature or deterioration which occurs over time. Thus, in an actualcase, test recording is performed on the OPC region 11 whileincreasingly and decreasingly changing the laser parameters stored inthe disc information zone 10, such as the power value and the like, soas to obtain an optimum recording power.

The defect management region 12 and the spare areas 13 are provided fordefect management i.e., provided for replacing a sector of the user dataarea 8 in which recording/reproduction cannot be appropriately performed(referred to as a “defect sector”) with another well-conditioned (i.e.,sufficiently usable) sector. In a rewritable single-layer optical disc,such as a 90 mm magneto-optical disc defined in the ISO/IEC 10090specifications, or the like, defect management is generally performed.

The spare areas 13 include a sector prepared as a replacement for adefect sector (referred to as a spare sector). A sector which wasemployed in place of a defect sector is referred to as a replacementsector. In a DVD-RAM, the spare areas 13 are placed at two positions,such that one is at the inner circumference side and the other is at theouter circumference side. The size of the spare area 13 at the outercircumference side is extendable such that an increase of defect sectorswhich goes beyond expectation can be handled.

The defect management region 12 includes: a disc definition structure(DDS) 20 having a format designed for defect management, which includesthe size of the spare area 13 and the position where the spare area 13is placed; and a defect list (DL) 21 which lists the positions of defectsectors and the positions of replacement sectors. In view of robustness,many discs are designed based on a specification such that each of theinner circumference portion and outer circumference portion of a dischas one defect management region 12, and each defect management region12 duplicatively stores the same content, i.e., the defect managementregions 12 of the disc have the four same contents in total.Alternatively, according to the specification for a 650 MB phase changeoptical disc (PD), a spare area is provided in the defect managementregion 12, and when a sector storing a DL 21 changes into a defectsector, the DL 21 is stored in a sector of the spare area.

The above structure is provided for a system including an optical discdrive in order to achieve data reliability on the same level as that ofa read-only optical disc in a rewritable optical disc under a conditionthat margins for physical characteristics are severe in a recordingoperation rather than a reproduction operation.

Although there are read-only information recording mediums having aplurality of recording layers, all existing rewritable informationrecording medium have only a single recording layer. The above-describeddefect management for a rewritable information recording medium isdirected to management of only one recording layer. There is no documentwhich discloses defect management in an information recording mediumhaving a plurality of recording layers. If defect management isperformed independently in each recording layer, a defect sector in acertain recording layer may not be replaced even when there is no morespare area in the certain recording layer but another recording layerstill has an available spare area. Further, in the case where tracks ofa disc is arranged in an opposite path arrangement (see FIGS. 4A through4D), if a spare area is assigned arbitrarily in each recording layer,the radial position of the first recording layer and the radial positionof the second recording layer deviate from each other at a transitionposition where laser light transits from the first recording layer tothe second recording layer. In such a case, the access speed decreases.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided amulti-layered information recording medium including a plurality ofrecording layers, the multi-layered information recording mediumcomprising: a user data area for recording user data; and a plurality ofspare areas including at least one replacement region, wherein when theuser data area includes at least one defect region, the at least onereplacement region may be used in place of the at least one defectregion, wherein the plurality of recording layers include a firstrecording layer and a second recording layer positioned contiguous toeach other, the first recording layer includes a first user data areawhich is a portion of the user data area, and a first spare area whichis one of the plurality of spare areas, the second recording layerincludes a second user data area which is another portion of the userdata area, and a second spare area which is another one of the pluralityof spare areas, the first spare area is positioned so as to becontiguous to the first user data area, the second spare area ispositioned so as to be contiguous to the second user data area, and thefirst spare area and the second spare area are positioned approximatelyat the same radial position on the multi-layered information recordingmedium.

In one embodiment of the present invention, logical addresses areassigned to the first user data area along a circumference directionfrom an inner circumference side to an outer circumference side of themulti-layered information recording medium; logical addresses areassigned to the second user data area along a circumference directionfrom the outer circumference side to the inner circumference side of themulti-layered information recording medium; the logical addressesassigned to the first user data area and the logical addresses assignedto the second user data area are in series; the first spare area ispositioned so as to be contiguous to a sector to which a maximum logicaladdress is assigned among a plurality of sectors included in the firstuser data area; and the second spare area is positioned so as to becontiguous to a sector to which a minimum logical address is assignedamong a plurality of sectors included in the second user data area.

According to another aspect of the present invention, there is provideda multi-layered information recording medium including a plurality ofrecording layers, the multi-layered information recording mediumincludes: a user data area for recording user data; and a plurality ofOPC regions provided for calibrating a recording power of laser light,wherein each of the plurality of recording layers includes acorresponding one of the plurality of OPC regions.

In one embodiment of the present invention, the multi-layeredinformation recording medium further comprises a calibration resultstorage region for storing a result of calibration of the recordingpower of the laser light, wherein the calibration result storage regionis provided in at least a reference layer selected from the plurality ofrecording layers.

In another embodiment of the present invention, the plurality ofrecording layers include a first recording layer and a second recordinglayer positioned contiguous to each other; the first recording layerincludes a first user data area which is a portion of the user dataarea; the second recording layer includes a second user data area whichis another portion of the user data area; logical addresses are assignedto the first user data area along a circumference direction from aninner circumference side to an outer circumference side of themulti-layered information recording medium; and logical addresses areassigned to the second user data area along a circumference directionfrom the outer circumference side to the inner circumference side of themulti-layered information recording medium.

In still another embodiment of the present invention, the plurality ofrecording layers include a first recording layer and a second recordinglayer positioned contiguous to each other; the first recording layerincludes a first user data area which is a portion of the user dataarea; the second recording layer includes a second user data area whichis another portion of the user data area; logical addresses are assignedto the first user data area along a circumference direction from aninner circumference side to an outer circumference side of themulti-layered information recording medium; and logical addresses areassigned to the second user data area along a circumference directionfrom the inner circumference side to the outer circumference side of themulti-layered information recording medium.

According to still another aspect of the present invention, there isprovided a multi-layered information recording medium including aplurality of recording layers, the multi-layered information recordingmedium comprising: a user data area for recording user data; and atleast one spare area including at least one replacement region, whereinwhen the user data area includes at least one defect region, the atleast one replacement region may be used in replacement of the at leastone defect region, wherein the user data area includes a plurality ofsectors, a logical address is assigned to each of the plurality ofsectors, and one of the at least one spare area is positioned so as tobe contiguous to a sector to which a maximum logical address is assignedamong the plurality of sectors included in the user data area, and saidspare area is expandable.

In one embodiment of the present invention, the spare area positionedcontiguous to the sector to which the maximum logical address isassigned is expandable in a direction from the spare area toward theuser data area.

In another embodiment of the present invention, the plurality ofrecording layers include a first recording layer and a second recordinglayer positioned contiguous to each other; the first recording layerincludes a first user data area which is a portion of the user dataarea; the second recording layer includes a second user data area whichis another portion of the user data area; logical addresses are assignedto the first user data area along a circumference direction from aninner circumference side to an outer circumference side of themulti-layered information recording medium; and logical addresses areassigned to the second user data area along a circumference directionfrom the outer circumference side to the inner circumference side of themulti-layered information recording medium.

In still another embodiment of the present invention, the plurality ofrecording layers include a first recording layer and a second recordinglayer positioned contiguous to each other; the first recording layerincludes a first user data area which is a portion of the user dataarea; the second recording layer includes a second user data area whichis another portion of the user data area; logical addresses are assignedto the first user data area along a circumference direction from aninner circumference side to an outer circumference side of themulti-layered information recording medium; and logical addresses areassigned to the second user data area along a circumference directionfrom the inner circumference side to the outer circumference side of themulti-layered information recording medium.

According to still another aspect of the present invention, there isprovided a recording apparatus for recording information in amulti-layered information recording medium including a plurality ofrecording layers, wherein: the multi-layered information recordingmedium includes a user data area for recording user data, and aplurality of spare areas including at least one replacement region,wherein when the user data area includes at least one defect region, theat least one replacement region may be used in place of the at least onedefect region, wherein the plurality of spare areas are provided in atleast two recording layers of the plurality of recording layers; therecording apparatus includes an optical head section capable ofoptically writing the information in the multi-layered informationrecording medium from one surface of the multi-layered informationrecording medium, and a control section for controlling execution of adefect management process using the optical head section; and the defectmanagement process includes steps of finding at least one availablespare area among the plurality of spare areas, determining whether ornot the user data area includes a defect region, if it is determinedthat the user data area includes a defect region, selecting a spare areawhose distance from the defect region is shortest among the at least onespare area found, and replacing the defect region with a replacementregion included in the selected spare area.

According to still another aspect of the present invention, there isprovided a recording apparatus for recording information in amulti-layered information recording medium including a plurality ofrecording layers, wherein: the multi-layered information recordingmedium includes a user data area for recording user data, and aplurality of spare areas including at least one replacement region,wherein when the user data area includes at least one defect region, theat least one replacement region may be used in place of the at least onedefect region, wherein the plurality of spare areas are provided in atleast two recording layers of the plurality of recording layers, andeach of the plurality of recording layers includes a portion of the userdata area; the recording apparatus includes an optical head sectioncapable of optically writing the information in the multi-layeredinformation recording medium from one surface of the multi-layeredinformation recording medium, and a control section for controllingexecution of a defect management process using the optical head section;and the defect management process includes steps of finding at least oneavailable spare area among the plurality of spare areas, determiningwhether or not the user data area includes a defect region, if it isdetermined that the user data area includes a defect region, determiningwhether or not a recording layer, in which an area including the defectregion which is a portion of the user data area exists, includes atleast one of the at least one spare area found, if it is determined thatthe recording layer, in which the area including the defect regionexists, includes none of the at least one spare area found, selecting aspare area whose distance from the defect region is shortest among theat least one spare area found, and replacing the defect region with areplacement region included in the selected spare area.

According to still another aspect of the present invention, there isprovided a recording method for recording information in a multi-layeredinformation recording medium including a plurality of recording layers,wherein: the multi-layered information recording medium includes a userdata area for recording user data, and a plurality of spare areasincluding at least one replacement region, wherein when the user dataarea includes at least one defect region, the at least one replacementregion may be used in place of the at least one defect region, whereinthe plurality of spare areas are provided in at least two recordinglayers of the plurality of recording layers; and the recording methodincludes steps of finding at least one available spare area among theplurality of spare areas, determining whether or not the user data areaincludes a defect region, if it is determined that the user data areaincludes a defect region, selecting a spare area whose distance from thedefect region is shortest among the at least one spare area found, andreplacing the defect region with a replacement region included in theselected spare area.

According to still another aspect of the present invention, there isprovided a recording method for recording information in a multi-layeredinformation recording medium including a plurality of recording layers,wherein: the multi-layered information recording medium includes a userdata area for recording user data, and a plurality of spare areasincluding at least one replacement region, wherein when the user dataarea includes at least one defect region, the at least one replacementregion may be used in place of the at least one defect region, whereinthe plurality of spare areas are provided in at least two recordinglayers of the plurality of recording layers, and each of the pluralityof recording layers includes a portion of the user data area; and therecording method includes steps of finding at least one available sparearea among the plurality of spare areas, determining whether or not theuser data area includes a defect region, if it is determined that theuser data area includes a defect region, determining whether or not arecording layer, in which an area including the defect region which is aportion of the user data area exists, includes at least one of the atleast one spare area found, if it is determined that the recordinglayer, in which the area including the defect region exists, includesnone of the at least one spare area found, selecting a spare area whosedistance from the defect region is shortest among the at least one sparearea found, and replacing the defect region with a replacement regionincluded in the selected spare area.

Thus, the invention described herein makes possible the advantages ofproviding: (1) a multi-layered information recording medium whereinplacement of spare areas in a plurality of recording layers is designedsuch that the spare areas are used efficiently and accesscharacteristics are improved; and (2) an information recording method,an information reproduction method, an information recording apparatusand an information reproduction apparatus for use with the abovemulti-layered information recording medium.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a structure of a track and sectors in a commonly employedoptical disc.

FIG. 2 illustrates a reproduction principle for an optical disc havingtwo recording layers.

FIG. 3A shows a groove pattern in a second recording layer in a parallelpath of a DVD disc.

FIG. 3B shows a groove pattern in a first recording layer in a parallelpath of a DVD disc.

FIG. 3C illustrates a recording/reproduction direction in a parallelpath of a DVD disc.

FIG. 3D illustrates assignment of sector numbers in a parallel path of aDVD disc.

FIG. 4A shows a groove pattern in a second recording layer in anopposite path of a DVD disc.

FIG. 4B shows a groove pattern in a first recording layer in an oppositepath of a DVD disc.

FIG. 4C illustrates a recording/reproduction direction in an oppositepath of a DVD disc.

FIG. 4D illustrates assignment of sector numbers in an opposite path ofa DVD disc.

FIG. 5 shows a region layout in a DVD-RAM.

FIG. 6 shows a region layout in a multi-layered information recordingmedium according to embodiment 1 of the present invention.

FIG. 7 shows a data structure of a DDS 20 according to embodiment 1 ofthe present invention.

FIG. 8 shows a spare full flag group 208 according to embodiment 1 ofthe present invention.

FIG. 9 shows a data structure of a DL 21 according to embodiment 1 ofthe present invention.

FIG. 10 illustrates assignment of sector numbers in embodiment 1 of thepresent invention.

FIG. 11A shows a layout of a recording layer included in an informationrecording medium having a single recording layer.

FIG. 11B shows a layout of recording layers included in a multi-layeredinformation recording medium according to embodiment 2 of the presentinvention.

FIG. 11C shows a variation of the layout of recording layers shown inFIG. 11B.

FIG. 12 shows a region layout of a multi-layered information recordingmedium according to embodiment 2 of the present invention.

FIG. 13 shows a data structure of a DDS 20 according to embodiment 2 ofthe present invention.

FIG. 14 shows a spare full flag group 208 according to embodiment 2 ofthe present invention.

FIG. 15 illustrates assignment of sector numbers in embodiment 2 of thepresent invention.

FIG. 16 shows a region layout of a multi-layered information recordingmedium according to embodiment 3 of the present invention.

FIG. 17 illustrates assignment of sector numbers in embodiment 3 of thepresent invention.

FIG. 18 shows an information recording/reproducing apparatus 500according to embodiment 4 of the present invention.

FIG. 19 is a flowchart for illustrating a procedure of obtaining defectmanagement information according to embodiment 4 of the presentinvention.

FIG. 20 is a flowchart for illustrating a reproduction procedure ofsectors according to embodiment 4 of the present invention, whereinreplacement is considered.

FIG. 21 is a flowchart for illustrating a procedure of converting LSNsto PSNs according to embodiment 4 of the present invention.

FIG. 22 is a flowchart for illustrating a procedure of updating defectmanagement information according to embodiment 4 of the presentinvention.

FIG. 23 is a flowchart for illustrating a recording procedure in sectorsaccording to embodiment 4 of the present invention, wherein replacementis considered.

FIG. 24A is a flowchart for illustrating an assignment procedure ofreplacement sectors according to embodiment 4 of the present invention.

FIG. 24B shows a variation of the flowchart shown in FIG. 24A.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

Hereinafter, a multi-layered information recording medium according toembodiment 1 of the present invention is described with reference to thedrawings. In the present invention, the multi-layered informationrecording medium refers to an information recording medium including twoor more recording layers.

FIG. 6 shows a region layout of a multi-layered information recordingmedium 50 according to embodiment 1 of the present invention. Themulti-layered information recording medium 50 includes two recordinglayers 51 and 52. The multi-layered information recording medium 50includes a user data area 5 for recording user data. In this embodimentof the present invention, the upper recording layer shown in FIG. 6 isreferred to as a first recording layer, and the lower recording layer isreferred to as a second recording layer. The first recording layer 51includes, from the inner circumference side to the outer circumferenceside along the recording/reproduction direction, a lead-in zone 101, ahead spare area 105, a first user data area 15, which is a portion ofthe user data area 5, an intermediate spare area 106, and a middleregion 102. The second recording layer 52 includes, from the outercircumference side to the inner circumference side along therecording/reproduction direction, a middle region 103, an intermediatespare area 106′, a second user data area 16, which is a portion of theuser data area 5, an end spare area 107, and a lead-out zone 104.

Each of the head spare area 105, the intermediate spare area 106, theintermediate spare area 106′, and the end spare area 107 includes atleast one replacement region (which is a “spare sector” in theembodiments of the present invention). When the user data area 5 has atleast one defect region (which is a “defect sector” in the embodimentsof the present invention), the spare sector can be used in place of thedefect sector.

The lead-in zone 101 includes a disc information zone 10, an OPC region11, and a defect management region 12. The defect management region 12is included in the middle region 102. The OPC region 11 is included inthe lead-out zone 104. The defect management region 12 includes a DDS 20and DL 21.

The disc information zone 10 is provided in the first recording layer51. The disc information zone 10 includes recording/reproductionparameters which are recommended for both the first and second recordinglayers 51 and 52. With such a structure, the parameters for all therecording layers 51 and 52 of the multi-layered information recordingmedium 50 can be obtained by simply accessing the first recording layer51. Thus, the processing speed can be advantageously increased.

The defect management region 12 is provided in the first recording layer51. The defect management region 12 includes defect managementinformation about defect management for both the first and secondrecording layers 51 and 52. That is, the DDS 20 describes informationabout the head spare area 105, the intermediate spare area 106, and theend spare area 107. Further, the DL 21 lists the positions of defectsectors and the positions of replacement sectors which are provided foruse in place of the defect sectors for both the first and secondrecording layers 51 and 52. With such a structure, all of theinformation about, defect management of the multi-layered informationrecording medium 50 can be obtained by simply accessing the firstrecording layer 51. Thus, the processing speed can be advantageouslyincreased.

The head spare area 105 and the intermediate spare area 106 are placedcontiguous to the both ends of the user data area 15. The intermediatespare area 106′ and the end spare area 107 are placed contiguous to theboth ends of the user data area 16. This arrangement has an advantagesuch that a sequential recording/reproduction operation along therecording/reproduction direction can be performed at a high-speed ascompared with a case where the spare areas 105 to 107 are placed suchthat the spare areas divide the user data area 15 or 16 at anintermediate portion. Further, the intermediate spare area 106 and theintermediate spare area 106′ are placed at the same radial position inthe multi-layered information recording medium 50. With thisarrangement, when the focal position of laser light transits from theuser data area 15 of the first recording layer 51 to the user data area16 of the second recording layer 52, the moving distance of the opticalhead along the radial direction is ideally zero (0), and therefore, ahigher accessing speed can be achieved. Herein, the moving distance isideally zero, i.e., may not be zero, because a deviation may occur whenthe first recording layer 51 and the second recording layer 52 arecombined, or the focal position of laser light deviates to an amountcorresponding to the eccentricity of the disc during the switching ofthe focal position of the laser light, and in such a case, a slightmovement of the laser light along the radial direction is necessary.

The OPC region 11 provided for calibrating the recording power of thelaser light is provided in both the first recording layer 51 and thesecond recording layer 52. This is because one of the recording layersis translucent, whereas the thickness of the other recording layer iscalibrated so as to reflect all of the laser light, and accordingly, therecording characteristics are different for each recoding layer. Thus,the OPC region 11 is provided in each of the first recording layer 51and the second recording layer 52 so that calibration of the recordingpower of the laser light can be performed independently in eachrecording layer.

It is desirable that storage regions for control information other thanthe disc information zone 10 and the defect management region 12, suchas a calibration result storage region 14 for storing the calibrationresult for the recording power of the laser light, are provided in thefirst recording layer 51 in view of the processing speed as describedabove.

Each of the sizes of the head spare area 105, the intermediate sparearea 106, and the end spare area 107 may be zero. For example, in thecase where the sizes of the head spare area 105 and the intermediatespare area 106 are not zero, and the size of the end spare area 107 iszero, the above described advantages of the present invention can beachieved.

FIG. 7 shows the data structure of the DDS 20 according to embodiment 1of the present invention. The data of the DDS 20 includes a DDSidentifier 201, a LSN0 position 202, ahead spare area size 203, and anintermediate spare area 203, an intermediated spare area size 204, anend spare area size 205, a first-layer end LSN 206, a second-layer endLSN 207, and a spare full flag group 208. The DDS identifier 201indicates that this data structure is DDS. The LSN0 position 202represents the PSN (i.e., physical address) of a sector whose LSN (i.e.,logical address) is 0. The head spare area size 203 represents thenumber of sectors in the head spare area 105. The intermediate sparearea size 204 represents the number of sectors in the intermediate sparearea 106. The end spare area size 205 represents the number of sectorsin the end spare area 107. The first-layer end LSN 206 represents theLSN assigned to the last sector in the user data area 15 of the firstrecording layer 51. The first-layer end LSN 206 is identical to thenumber of sectors in the user data area 15. The second-layer end LSN 207represents the LSN assigned to the last sector in the user data area 16of the second recording layer 52. The second-layer end LSN 207 is equalto a value obtained by adding the number of sectors in the user dataarea 15 to the number of sectors in the user data area 16. The sparefull flag group 208 is a group of flags which represent whether or notthere is an available spare sector in the spare areas 105 to 107.

FIG. 8 shows an example of the spare full flag group 208. A head sparearea full flag 221 corresponds to the head spare area 105. A first-layerintermediate spare area full flag 222 corresponds to the intermediatespare area 106. A second-layer intermediate spare area full flag 223corresponds to the intermediate spare area 106′. A second-layer endspare area full flag 224 corresponds to the end spare area 107. Thepresent invention is not limited to this flag arrangement so long as thespare full flag group 208 includes flags corresponding to the spareareas 105 to 107.

FIG. 9 shows the data structure of the DL 21 according to embodiment 1of the present invention. The data of the DL 21 includes a DL identifier301, a DL entry number 302, and 0 (zero) or more DL entries 303. The DLidentifier 301 indicates that this data structure is DL. The DL entrynumber 302 represents the number of DL entries 303. The DL entries 303each include information about a defect sector position 304 and areplacement sector position 305. The PSN of a defect sector is stored asthe defect sector position 304. As the replacement sector position 305,the PSN of a replacement sector is stored. The PSN includes a layernumber 306 and an intralayer sector number 307. The layer number 306 maybe any value so long as the layer can be identified by the value. Forexample, the layer number 306 of the first recording layer 51 is 0, andthe layer number 306 of the second recording layer 52 is 1. Theintralayer sector number 307 may be any value so long as sectors in acertain recording layer can be identified by the value. For example, theintralayer sector number 307 incrementally increases by one every timeone sector is passed along the recording/reproduction direction. Even ifthe relationship between the PSN of a sector in the first recordinglayer 51 and the PSN of a sector in the second recording layer 52 placedat the same radial position is two's complement, the above-describedconditions are satisfied as in the opposite paths of a DVD-ROM. Forexample, consider that the PSN is represented in the 28-bit format, andthe PSN of the first recording layer 51 is within the range of 0000000hto 0FFFFFFh (“h” means that the value is represented by a hexadecimalnumber). When the PSN of a certain sector in the first recording layer51 is 0123450h, the PSN of a corresponding sector in the secondrecording layer 52 at the same radial position is FEDCBAFh (see thefollowing steps 1) to 4)):

-   1) 0 1 2 3 4 5 0:hexadecimal number-   2) 0000 0001 0010 0011 0100 0101 0000 :binary number-   3) 1111 1110 1101 1100 1011 1010 1111 :bit-inverted binary number-   4) F E D C B A F :hexadecimal number    The most significant bit of the PSN of the first recording layer 51    is always zero, and the most significant bit of the PSN of the    second recording layer 52 is always F. This most significant bit is    equal to the layer number 306. In the first recording layer 51, when    the track is followed along the recording/reproduction direction    (from the inner circumference side to the outer circumference side),    the PSN of the next sector is 0123451h. In the second recording    layer 52, when the track is followed along the    recording/reproduction direction (from the outer circumference side    to the inner circumference side), the PSN of the next sector is    FEDCBB0h. The sector number 307 can be obtained by simply removing    the most significant bit (i.e., the layer number 306) from the PSN.    In the first recording layer 51, the sector number 307 of a current    sector is 123450h, and the sector number 307 of a next sector is    123451h. In the second recording layer 52, the sector number 307 of    a current sector is EDCBAFh, and the sector number 307 of a next    sector is EDCBB0h.

When the DL 21 of the present invention is used, a defect sector can bereplaced with a spare sector in a spare area provided in the samerecording layer in which the defect sector is included, and moreover, adefect sector can be replaced with a spare sector of a recording layerdifferent from the recording layer in which the defect sector isincluded. For example, a DL entry 303 wherein the defect sector position304 represents the PSN in the first recording layer 51, and thereplacement sector position 305 represents the PSN in the secondrecording layer 52, means that a defect sector in the first user dataarea 15 of the first recording layer 51 was replaced with a spare sectorin the second recording layer 52. If a defect list is formed by DLentries based on which a recording layer cannot be identified, as in theconventional art, replacement processing cannot be successfullyperformed when the number of defect sectors is greater than the numberof spare sectors provided in a recording layer. Thus, according toembodiment 1 of the present invention, defect sectors can be replacedwith spare sectors until all the spare sectors of all the recordinglayers are used. That is, the spare areas can be efficiently used.

FIG. 10 illustrates the assignment of the sector numbers according toembodiment 1 of the present invention. The sector numbers assigned fromthe inner circumference to the outer circumference in the firstrecording layer 51 and then from the outer circumference to the innercircumference in the second recording layer 52 are arranged horizontallyfrom left to right in the drawing. Thus, from left to right in thedrawing, the head spare area 105, the first user data area 15, theintermediate spare area 106, the intermediate spare area 106′, thesecond user data area 16, and the end spare area 107 occur in thisorder. Each of these regions and areas include a plurality of sectors.In the first recording layer 51, the PSN increases by 1 every time asingle sector is passed toward the outer circumference side; whereas inthe second recording layer 52, the PSN increases by 1 every time asingle sector is passed toward the inner circumference side. Theassignment may be made such that values obtained by removing the layernumber (i.e., the most significant bit) from the PSNs of the firstrecording layer 51 are in the same numeric range as values obtained byremoving the layer number (i.e., the most significant bit) from the PSNsof the second recording layer 52. (That is, the minimum PSN within thesectors included in the head spare area 105 of the first recording layer51 is identical to the minimum PSN within the sectors included in theintermediate spare area 106′ of the second recording layer 52 except forthe layer number; and the maximum PSN within the sectors included in theintermediate spare area 106 of the first recording layer 51 is identicalto the maximum PSN within the sectors included in the end spare area 107of the second recording layer 52 except for the layer number.) Therelationship of the PSN of a sector in the first recording layer 51 andthe PSN of a sector in the second recording layer 52 placed at the sameradial position may be two's complement as in the opposite paths of aDVD-ROM.

The LSNs are assigned only to a plurality of sectors included in theuser data area 5. In the first user data area 15, the LSNs are assignedalong the circumference direction of the multi-layered informationrecording medium 50. In the second user data area 16 also, the LSNs areassigned along the circumference direction of the multi-layeredinformation recording medium 50. The LSNs assigned to the first userdata area 15 and the LSNs assigned to the second user data area 16 areconsecutive numbers.

In the first user data area 15 of the first recording layer 51, 0 (zero)is assigned to a sector at the innermost circumference position as aLSN. The LSN incrementally increases by 1 every time one sector ispassed from the inner circumference side to the outer circumferenceside. In the second user data area 16 of the second recording layer 52,a value obtained by adding 1 to the maximum LSN within the first userdata area 15 of the first recording layer 51 is assigned to a sector atthe outermost circumference position as a LSN. The LSN incrementallyincreases by 1 every time one sector is passed from the outercircumference side to the inner circumference side. In this way, in thesecond user data area 16, the logical addresses (i.e., LSNs) areassigned along a direction opposite to the assignment direction in thefirst user data area 15.

The intermediate spare area 106 is positioned contiguous to a sectorhaving the maximum logical address (i.e., maximum LSNs) in the firstuser data area 15. The intermediate spare area 106′ is positionedcontiguous to a sector having the minimum logical address (i.e., minimumLSNs) in the second user data area 16. As described above, theintermediate spare area 106 and the intermediate spare area 106′ areplaced at the same radial position of the multi-layered informationrecording medium 50. Accordingly, the sector having the maximum logicaladdress in the first user data area 15 and the sector having the minimumlogical address in the second user data area 16 are at the same radialposition of the multi-layered information recording medium 50. Due tothis arrangement, the moving distance of laser light along the radialdirection is ideally zero when the focal position of the laser light isswitched from the sector having the maximum logical address in the firstuser data area 15 to the sector having the minimum logical address inthe second user data area 16.

Even if user data has already been recorded in the user data area 5, thesize of the spare areas can be increased. This is explained withreference to FIG. 10. The end spare area 107 is placed contiguous to asector having the maximum LSN in the user data area 5. The end sparearea 107 can be expanded in a direction from the end spare area 107toward the second user data area 16 (i.e., the direction indicated byarrow 107′ in FIG. 10).

First, before the end spare area 107 is expanded in the directionindicated by arrow 107′, user data recorded in a portion of the seconduser data area 16 which will be converted to the end spare area 107 istransferred to another portion of the user data area 5. Then, the filemanagement information of the transferred user data is modified suchthat the file management information of the transferred user data (whichis one of the information managed by a file system) refers to a sectorposition to which the user data has been transferred. Next, change ofthe size of the user data area 5 is reflected in the volume spacemanagement information (which is one of the information managed by afile system). Then, in the last step, the size of the end spare area 107is increased. It should be noted that increasing the sizes of the headspare area 105 and the intermediate spare areas 106 and 106′ is notpractical because, if the sizes of these regions are increased, theassignment of the LSNs to the user data area 5 are changed, and as aresult, the file system for managing the user data area 5 using the LSNswould corrupt.

As described above, according to embodiment 1 of the present invention,in a multi-layered information recording medium having two recordinglayers, continuous accessibility can be improved. Furthermore, a defectsector can be replaced with a spare area in any recording layer, andtherefore, the spare areas can be efficiently used. Furthermore, thesize of the spare area can be increased so as to prevent lack of spareareas, whereby reliability of data can be improved.

Embodiment 2

Hereinafter, a multi-layered information recording medium according toembodiment 2 of the present invention is described with reference to thedrawings.

First, a reference layer which is used as a reference among a pluralityof recording layers included in a multi-layered information recordingmedium is described. FIGS. 11A, 11B and 11C illustrate a layout ofrecording layers of an information recording medium according toembodiment 2. FIG. 11A illustrates a layout of layers included in aninformation recording medium 53 having a single recording layer 402. InFIG. 11A, the information recording medium 53 includes a transparentresin 401, a total reflection recording layer 402, and a substrate 400along a direction through which laser light enters the informationrecording medium 53. The total reflection recording layer 402 ispositioned at depth d from the surface of the transparent resin 401through which the laser light enters. FIGS. 11B and 11C illustratelayouts of the layers included in information recording mediums 54 and55 each of which has three recording layers 402, 403 and 404. In theselayouts, the translucent recording layers 403 and 404 are provided inthis order, toward coming laser light, on the total reflection recordinglayer 402 which is formed on the substrate 400, such that thetranslucent recording layers 403 and 404 are sandwiched by thetransparent resin 401. In the information recording medium 54 of FIG.11B, the total reflection recording layer 402 is at depth d from thesurface of the outermost transparent resin layer 401 through which thelaser light enters the information recording medium 54. In theinformation recording medium 55 of FIG. 11C, the translucent recordinglayer 403 is at depth d from the surface of the outermost transparentresin layer 401 through which the laser light enters the informationrecording medium 55. This is a typical difference between theinformation recording medium 54 and the information recording medium 55.

In general, an optical head section is designed such that an optimumlight spot is obtained at depth d. Herein, a recording layer at depth dis referred to as a reference layer for convenience of explanation.Regions where important information is to be stored, for example, a discinformation zone 10 and a defect management region 12, are desirablypositioned in the reference layer. In FIG. 6, the first recording layer51, in which the disc information zone 10, the defect management region12, and the calibration result storage region 14 are positioned, is areference layer.

In the description below, the recording layers are referred to as afirst recording layer, a second recording layer, a third recordinglayer, . . . , in the order of largeness of the LSN from the minimumLSN. For example, in the information recording medium 54 shown in FIG.11B, the total reflection recording layer 402 is referred to as thefirst recording layer, the translucent recording layer 403 is referredto as the second recording layer, and the translucent recording layer404 is referred to as the third recording layer. Further, for example,in the information recording medium 55 illustrated in FIG. 1C, thetranslucent recording layer 403 is referred to as the first recordinglayer, the translucent recording layer 404 is referred to as the secondrecording layer, and the total reflection recording layer 402 isreferred to as the third recording layer. Thus, the numbering forrecording layers does not necessarily depend on the positionalrelationship of the recording layers. In the above explanation, exampleshaving three recording layers have been described. However, the aboveexplanation similarly applies to any information recording mediumincluding two or more recording layers.

FIG. 12 illustrates a region layout of a multi-layered informationrecording medium 56 according to embodiment 2 of the present invention.The multi-layered information recording medium 56 includes threerecording layers 57, 58 and 59. The multi-layered information recordingmedium 56 includes a user data area 5 for recording user data. The firstrecording layer 57 includes a lead-in zone 101, a head spare area 105, afirst user data area 17 which is a portion of the user data area 5, anintermediate spare area 106, and a middle region 102, from the innercircumference side to the outer circumference side, which is the samedirection as the recording/reproduction direction. The second recordinglayer 58 includes a middle region 103, an intermediate spare area 106′,a second user data area 18 which is a portion of the user data area 5,an intermediate spare area 108, and a middle region 109, from the outercircumference side to the inner circumference side, which is the samedirection as the recording/reproduction direction. The third recordinglayer 59 includes a middle region 109, an intermediate spare area 108′,a third user data area 19 which is a portion of the user data area 5, anend spare area 107, and a lead-out zone 104, from the innercircumference side to the outer circumference side, which is the samedirection as the recording/reproduction direction. The lead-in zone 101includes a disc information zone 10, an OPC region 11 and a defectmanagement region 12. The middle region 102 includes a defect managementregion 12. The middle region 109 includes an OPC region 11. The defectmanagement region 12 includes a DDS 20 and a DL 21.

The disc information zone 10 is provided in the first recording layer57. The disc information zone 10 stores recording/reproductionparameters, which are recommended for each of all the recording layers57, 58 and 59. With such an arrangement, parameters for all therecording layers 57, 58 and 59 of the multi-layered informationrecording medium 56 can be obtained by simply accessing the firstrecording layer 57, and thus, the processing speed can be advantageouslyincreased.

The defect management region 12 is provided in the first recording layer57, and includes defect management information for defect management inall the recording layers 57, 58 and 59. That is, the DDS 20 describes ahead spare area 105, intermediate spare areas 106, 106′, 108 and 108′,and information about the end spare area 107. The DL 21 lists thepositions of defect sectors in all of the recording layers 57, 58 and59, and the positions of replacement sectors which are used in place ofthe defect sectors. With such an arrangement, all information aboutdefect management of the multi-layered information recording medium 56can be obtained by simply accessing the first recording layer 57, andthus, the processing speed can be advantageously increased.

Each of the spare areas 105 to 108′ of the recording layers 57 to 59 isprovided at the position contiguous to either end portion of the firstto third user data areas 17 to 19. This arrangement is advantageousbecause sequential recording/reproduction along therecording/reproduction direction can be performed at a high speed, ascompared with a case where a spare area is provided at a position suchthat any of the first to third user data areas 17 to 19 is interruptedby the spare area. Further, the intermediate spare areas 106 and 106′are provided at the same radial position in an area of the outercircumference side of the recording layers 57 and 58. With such anarrangement, the moving distance of an optical head section along theradial direction is ideally zero when the focal position of the laserlight is switched from the first user data area 17 to the second userdata area 18. Thus, accessing at a higher speed can be realized.Further, the intermediate spare areas 108 and 108′ are provided at thesame radial position in an area of the inner circumference side of therecording layers 58 and 59. With such an arrangement, the movingdistance of an optical head section along the radial direction isideally zero when the focal position of the laser light is switched fromthe second user data area 18 to the third user data area 19. Thus, theprocessing speed can be advantageously increased.

Herein, the moving distance is ideally zero, i.e., may not be zero,because a deviation may occur when the recording layers 57 to 59 arecombined, or because the focal position of laser light deviates to anamount corresponding to the eccentricity of the disc during theswitching of the focal position of the laser light, and in such a case,a slight movement of the laser light along the radial direction isnecessary.

An OPC region 11 is provided in each of all the recording layers 57 to59 because the recording layers 57 to 59 have different recordingcharacteristics. Thus, the OPC region 11 is provided in each of therecording layers 57 to 59 such that calibration of the recording powercan be performed separately in any recording layer.

Each of the sizes of the head spare area 105, the intermediate spareareas 106, 106′, 108 and 108′, and the end spare area 107 may be zero.For example, in the case where each of the sizes of the head spare area105 and the intermediate spare areas 106, 106′, 108 and 108′ are notzero, and the size of the end spare area 107 is zero, the abovedescribed advantages of the present invention can be achieved.

FIG. 13 shows a data structure of a DDS 20 according to embodiment 2 ofthe present invention. The DDS 20 includes a DDS identifier 201, arecording layer number 209, a LSN0 position 202, a head spare area size203, an intermediate spare area size 210 at the inner circumferenceside, an outer circumference side intermediate spare area size 211, theend spare area size 205, a first layer user data area size 212, anintermediate layer user data area size 213, the end layer user data areasize 214, and a spare full flag group 208. In FIG. 13, like elements areindicated by like reference numerals used in embodiment 1, and detaileddescriptions thereof are omitted. The recording layer number 209indicates the total number of recording layers. The inner circumferenceside intermediate spare area size 210 indicates the number of sectors inthe intermediate spare areas 108 and 108′ at the inner circumferenceside. The outer circumference side intermediate spare area size 211indicates the number of sectors in the intermediate spare areas 106 and106′ at the inner circumference side. The first layer user data areasize 212 indicates the number of sectors in the first user data area 17.The first layer user data area size 212 is equal to the maximum value ofthe LSN assigned to the first user data area 17, and therefore, is equalto the first layer last LSN 206 in embodiment 1. The intermediate layeruser data area size 213 indicates the number of sectors in the seconduser data area 18. The intermediate layer user data area size 213indicates the number of sectors in the second user data area 18. The endlayer user data area size 214 indicates the number of sectors in thethird user data area 19.

The DDS 20 shown in FIG. 13 can be applied to any multi-layeredinformation recording medium having two or more recording layers. Forexample, consider that the DDS 20 is applied to a multi-layeredinformation recording medium having four recording layers. In this case,the recording layer number 209 is four. The intermediate layer user dataarea size 213 indicates the number of sectors in the user data area ofthe second recording layer, and also indicates the number of sectors inthe user data area of the third recording layer. The end layer user dataarea size 214 indicates the number of sectors in the user data area ofthe fourth recording layer.

If the region layout is limited such that the number of sectors includedin the intermediate spare areas 108 and 108′ at the inner circumferenceside is the same as the number of sectors included in the intermediatespare areas 106 and 106′ at the outer circumference side, twoinformation fields, the inner circumference side intermediate spare areasize 210 and the outer circumference side intermediate spare area size211, can be gathered into a single information field because in such acase the size 210 and the size 211 are always equal. This informationfield is equivalent to the intermediate spare area size 204 described inembodiment 1. If the region layout is limited such that the number ofsectors included in the head spare area 105 is the same as the number ofsectors included in the intermediate spare areas 108 and 108′ at theinner circumference side, the head spare area size 203 and theintermediate spare area size 210 can be gathered into a singleinformation field. Further, the first layer user data area size 212 andthe intermediate layer user data area size 213 may be gathered into asingle information field. Thus, information fields which include theidentical contents when a certain limitation is made to the regionlayout can be reduced into a single information field including such acontent, and a field obtained by four rules of arithmetic (addition,subtraction, multiplication, and division) may be omitted.

FIG. 14 illustrates an example of the spare full flag group 208. Thehead spare area full flag 221 corresponds to the head spare area 105.The first-layer intermediate spare area full flag 222 corresponds to theintermediate spare area 106. An intermediate spare area full flag 225for the outer circumference side of the second layer corresponds to theintermediate spare area 106′. An intermediate spare area full flag 226for the inner circumference side of the second layer corresponds to theintermediate spare area 108. An intermediate spare area full flag 227for the inner circumference side of the third layer corresponds to theintermediate spare area 108′. The end spare area full flag 224corresponds to the end spare area 107.

The data structure shown in FIG. 9 can also be applied to the DL 21 ofembodiment 2 as in embodiment 1. If the layer number 306 is representedin the 4-bit format, 16 recording layers at the most can be expressed.In embodiment 2 also, defect sectors can be replaced with spare sectorsuntil the spare sectors of all the recording layers are used up. It isclearly appreciated that in such an arrangement, the spare areas can beefficiently used.

FIG. 15 shows assignment of sector numbers according to embodiment 2 ofthe present invention. The sector numbers assigned from the innercircumference to the outer circumference in the first recording layer57, from the outer circumference to the inner circumference in thesecond recording layer 58, and then from the inner circumference to theouter circumference in the third recording layer 59, are arrangedhorizontally from left to right in the drawing. Thus, from left to rightin the drawing, the head spare area 105, the first user data area 17,the intermediate spare area 106, the intermediate spare area 106′, thesecond user data area 18, the intermediate spare area 108, theintermediate spare area 108′, the third user data area 19, and the endspare area 107 occur in this order. In the first recording layer 57, thePSN increases by 1 every time a single sector is passed toward the outercircumference side. In the second recording layer 52, the PSN increasesby 1 every time a single sector is passed toward the inner circumferenceside. In the third recording layer 59, the PSN increases by 1 every timea single sector is passed toward the outer circumference side. Theassignment directions of LSNs are opposite between contiguous recordinglayers. The assignment may be made such that values obtained by removingthe layer number from the PSNs are in the same numeric range among thefirst to third recording layers 57 to 59. Alternatively, a rule ofassigning PSNs in the opposite paths of a DVD-ROM may be extended suchthat the relationship between the values of lower bits of the PSN of asector in an odd-numbered layer and the values of lower bits of the PSNof a sector in an even-numbered layer at the same radial position may betwo's complement. In this case, as values of higher bits of the PSNs, 0may be assigned to the first and second recording layers, 1 may beassigned to the third and fourth recording layers, and 2 may be assignedto the fifth and sixth recording layers.

The LSNs are assigned only to sectors included in the user data area 5.In the first user data area 17, 0 is assigned as the LSN of the sectorat the innermost circumference position, and the LSN increases by 1every time a single sector is passed from the inner circumference sideto the outer circumference side. In the second user data area 18, avalue obtained by adding 1 to the maximum LSN of the first user dataarea 17 is assigned as the LSN of the sector at the outermostcircumference position, and the LSN increases by 1 every time a singlesector is passed from the outer circumference side to the innercircumference side. In the third user data area 19, a value obtained byadding 1 to the maximum LSN of the second user data area 18 is assignedas the LSN of the sector at the innermost circumference position, andthe LSN increases by 1 every time a single sector is passed from theinner circumference side to the outer circumference side.

Although a detailed description is herein omitted because it issubstantially the same as that provided in embodiment 1, even if userdata has already been recorded in the user data area 5 of amulti-layered information recording medium including three or morerecording layers, the size of the outermost circumference spare area 107can be increased.

As described above, according to embodiment 2, continuous accessibilitycan be improved in a multi-layered information recording mediumincluding two or more recording layers. Furthermore, a defect sector canbe replaced with a spare area in any recording layer, and therefore, thespare areas can be efficiently used. Furthermore, the size of the sparearea can be increased so as to prevent lack of spare areas, wherebyreliability of data can be improved.

Embodiment 3

Hereinafter, a multi-layered information recording medium according toembodiment 3 of the present invention is described with reference to thedrawings.

FIG. 16 shows a region layout of a multi-layered information recordingmedium 60 according to embodiment 3 of the present invention. Themulti-layered information recording medium 60 includes two recordinglayers 61 and 62. The recording/reproduction direction is the same inboth the first and second recording layers 61 and 62. The multi-layeredinformation recording medium 60 includes a user data area 5 forrecording user data. The first recording layer 61 includes, from theinner circumference side to the outer circumference side, a lead-in zone101, a head spare area 105, a first user data area 23, which is aportion of the user data area 5, an intermediate spare area 106, and alead-out zone 111. The second recording layer 62 includes, from theinner circumference side to the outer circumference side, a lead-in zone110, an intermediate spare area 108, a second user data area 24, whichis a portion of the user data area 5, an end spare area 107, and alead-out zone 104. The lead-out zone 111 includes a defect managementregion 12. The lead-in zone 110 includes an OPC region 11. In FIG. 16,like elements are indicated by like reference numerals used inembodiment 1 or 2, and detailed descriptions thereof are omitted.

The DDS 20 of embodiment 2 shown in FIG. 13 can also be used as the datastructure of embodiment 3. In embodiment 3, it is not necessary toprovide the intermediate layer user data area size 213.

In embodiment 3, the flag group shown in FIG. 8 is used as the sparefull flag group 208 of embodiment 3.

In embodiment 3, the data structure shown in FIG. 9 is used as the DL 21of embodiment 3. In embodiment 3 also, defect sectors can be replacedwith spare sectors until the spare sectors of all the recording layersare used up. It is clearly appreciated that in such an arrangement, thespare areas can be efficiently used.

FIG. 17 shows assignment of sector numbers according to embodiment 3 ofthe present invention. The sector numbers assigned from the innercircumference to the outer circumference in the first recording layer61, and then from the inner circumference to the outer circumference inthe second recording layer 62, are arranged horizontally from left toright in the drawing. Thus, from left to right in the drawing, the headspare area 105, the first user data area 23, the intermediate spare area106, the intermediate spare area 108, the second user data area 24, andthe end spare area 107 occur in this order. In both the first recordinglayer 61 and the second recording layer 62, the PSN increases by 1 everytime a single sector is passed from the inner circumference side to theouter circumference side. The PSNs in the first and second layers at thesame radial position are equal except for layer numbers. The LSNs areassigned only to sectors included in the user data area 5. In the firstuser data area 23, 0 is assigned as the LSN of the sector at theinnermost circumference position, and the LSN increases by 1 every timea single sector is passed from the inner circumference side to the outercircumference side. In the second user data area 24, a value obtained byadding 1 to the maximum LSN of the first user data area 23 is assignedas the LSN of the sector at the innermost circumference position, andthe LSN increases by 1 every time a single sector is passed from theinner circumference side to the outer circumference side.

It is clear from the comparison made between FIGS. 10 and 17, even ifthe recording/reproduction direction in a recording layer is differentbetween the multi-layered information recording medium 50 of embodiment1 and the multi-layered information recording medium 60 of embodiment 3,the relationship between assignment of LSNs and disposition of the spareareas is the same. Thus, as described in embodiment 1, even if user datahas already been recorded in the user data area 5, the size of spareareas can be increased.

As described above, according to embodiment 3, for multi-layeredinformation recording mediums having two or more recording layers, acommon defect management method can be applied to both a multi-layeredinformation recording medium wherein the recording/reproductiondirection is the same in all of the recording layers and a multi-layeredinformation recording medium wherein the recording/reproductiondirection is alternately inverted for the respective recording layers.Thus, a defect sector can be replaced with a spare area of any recordinglayer, and therefore, the spare areas can be efficiently used.Furthermore, the size of the spare area can be increased so as toprevent lack of spare areas, whereby reliability of data can beimproved.

Embodiment 4

Hereinafter, an embodiment of an information recording/reproducingapparatus, which performs recording/reproduction using the multi-layeredinformation recording medium 50 described in embodiment 1, is describedwith reference to the drawings.

FIG. 18 is a block diagram showing an information recording/reproducingapparatus 500 according to embodiment 4 of the present invention. Theinformation recording/reproducing apparatus 500 includes a disc motor502, a preamplifier 508, a servo circuit 509, a binarization circuit510, a modulation/demodulation circuit 511, an ECC circuit 512, a buffer513, a CPU 514, an internal bus 534, and an optical head section 535. Inthe information recording/reproducing apparatus 500, the multi-layeredinformation recording medium 50 is inserted. The optical head section535 includes a lens 503, an actuator 504, a laser driving circuit 505, alight detector 506, and a transport table 507. Reference numeral 520denotes a rotation detection signal. Reference numeral 521 denotes adisc motor driving signal. Reference numeral 522 denotes a laseremission permitting signal. Reference numeral 523 denotes a lightdetection signal. Reference numeral 524 denotes a servo error signal.Reference numeral 525 denotes an actuator driving signal. Referencenumeral 526 denotes a transport table driving signal. Reference numeral527 denotes an analog data signal. Reference numeral 528 denotes abinarization data signal. Reference numeral 529 denotes a demodulationdata signal. Reference numeral 530 denotes a correction data signal.Reference numeral 531 denotes a storage data signal. Reference numeral532 denotes an encode data signal. Reference numeral 533 denotes amodulation data signal.

The CPU 514 functions as a control section. The CPU 514 controls theentire operation of the information recording/reproducing apparatus 500via the internal bus 534 according to an incorporated control program.As described below, the optical head section 535 can optically writeinformation in the multi-layered information recording medium 50 fromone side of the multi-layered information recording medium 50. Theoptical head section 535 can optically read information from themulti-layered information recording medium 50. The CPU 514 controlsexecution of a defect management process using the optical head section535 as described below.

In response to the laser emission permitting signal 522 output from theCPU 514, the laser driving circuit 505 emits laser light 536 onto themulti-layered information recording medium 50. The light reflected bythe multi-layered information recording medium 50 is converted by thelight detector 506 to the light detection signal 523. The lightdetection signal 523 is subjected to addition/subtraction in thepreamplifier 508 so as to generate the servo error signal 524 and theanalog data signal 527. The analog data signal 527 is A/D(analog/digital) converted by the binarization circuit 510 to thebinarization data signal 528. The binarization data signal 528 isdemodulated by the modulation/demodulation circuit 511 to generate thedemodulation data signal 529. The demodulation data signal 529 isconverted by the ECC circuit 512 to the correction data signal 530 whichdoes not include any error. The correction data signal 530 is stored ina buffer 513. The servo circuit 509 outputs the actuator driving signal525 based on the servo error signal 524, thereby feeding a servo errorback to the actuator 504 for focusing control or tracking control of thelens 503. An error correction code is added by the ECC circuit 512 tothe storage data signal 531 which is an output of data from the buffer513, so as to generate the encode data signal 532. Then, the encode datasignal 532 is modulated by the modulation/demodulation circuit 511 togenerate the modulation data signal 533. The modulation data signal 533is input to the laser driving circuit 505 so as to modulate the power oflaser light.

The information recording/reproducing apparatus 500 may be used as aperipheral device of a computer, such as a CD-ROM drive or the like. Insuch a case, a host interface circuit (not shown) is additionallyprovided, and data is transmitted between a host computer (not shown)and the buffer 513 through a host interface bus (not shown) such as aSCSI or the like. Alternatively, if the informationrecording/reproducing apparatus 500 concomitantly works as a consumerdevice such as a CD player or the like, an AV decoder/encoder circuit(not shown) is additionally provided for compressing a moving image orsound or decompressing a compressed moving image or sound in order totransmit data between the host computer and the buffer 513.

In a reproduction operation of the information recording/reproducingapparatus 500 according to embodiment 4 of the present invention, it isnecessary to provide two processes, a process of obtaining defectmanagement information and a process of reproducing sectors whileconsidering replacement, in order to reproduce information recorded inthe multi-layered information recording medium 50 including tworecording layers to which defect management of the present invention isapplied.

In a recording operation of the information recording/reproducingapparatus 500 according to embodiment 4 of the present invention, it isnecessary to provide, in addition to the above reproduction operation,two processes, a process of updating defect management information and aprocess of recording sectors while considering replacement, in order torecord information in the multi-layered information recording medium 50including two recording layers to which defect management of the presentinvention is applied.

FIG. 19 shows a flowchart 600 for illustrating a procedure of obtainingdefect management information in embodiment 4 of the present invention.In this embodiment, the disc information zone 10, in which discinformation is stored, and a defect management region 12, in whichdefect management information is stored, are provided in a referencelayer.

At the first step of the process of obtaining defect managementinformation, i.e., at step 601, the CPU 514 instructs the servo circuit509 to control the focal point of laser light so as to follow a track ofa reference layer.

At step 602, the optical head section 535 reproduces a sector whichstores disc information, and the CPU 514 confirms parameters and formatswhich are necessary for recording/reproduction in the multi-layeredinformation recording medium 50.

At step 603, the optical head section 535 reproduces a sector whichstores defect management information. The reproduced data is retained ina predetermined place of the buffer 513.

FIG. 20 is a flowchart 700 for illustrating a reproduction procedure ofsectors according to embodiment 4 of the present invention, whereinreplacement is considered. In this reproduction process, assume thatdefect management information including the DDS 20 and DL 21 havealready been retained in the buffer 513.

At the first step of this reproduction process, i.e., at step 701, theCPU 514 converts the LSNs to PSNs (detailed descriptions of this stepwill be described later with reference to FIG. 21).

At step 702, the CPU 514 refers to the layer number of the PSN todetermine whether or not a recording layer in which the focal point ofthe laser light 536 exists is identical to a recording layer to bereproduced. If identical, the process proceeds to step 704: if not, theprocess proceeds to step 703.

At step 703, the CPU 514 instructs the servo circuit 509 to let thefocal point of the laser light 536 to follow a track of a recordinglayer to be reproduced.

At step 704, the optical head section 535 reproduces informationrecorded in a sector indicated by the PSN obtained at conversion step701.

FIG. 21 is a flowchart 800 for illustrating a procedure of convertingLSNs to PSNs (i.e., step 701 of FIG. 20) according to embodiment 4 ofthe present invention. In this embodiment, assume that in the firstrecording layer, the PSN increases by 1 every time one sector is passedfrom the inner circumference side to the outer circumference side, whilein the second recording layer, the PSN increases by 1 every time onesector is passed from the outer circumference side to the innercircumference side.

At the first step of this replacement process, i.e., at step 801, theLSNs are converted to PSNs without considering a result of replacementof defect sectors indicated in the DL 21 with spare areas (i.e., in thesame manner as that performed when no defect sector exists). Referringto FIG. 10, if an LSN to be converted is smaller than the total numberof sectors included in the first user data area 15, a corresponding PSNis obtained by calculation of (the minimum PSN of the first user dataarea 15) plus (the LSN). If an LSN to be converted is greater than thetotal number of sectors included in the first user data area 15, acorresponding PSN is obtained by calculation of (the minimum PSN of thesecond user data area 16) plus (the LSN) minus (the total number ofsectors included in the first user data area 15).

At step 802, the CPU 514 refers to the DL entries 303 of the DL 21 todetermine whether or not a sector indicated by the above-calculated PSNhas been replaced with a spare sector. If so, the process proceeds tostep 803; if not, the replacement process ends.

At step 803, a replacement sector position of the DL entry 303, whichindicates that the sector having the above PSN has been replaced, isemployed as a PSN.

As described above, the information recording/reproducing apparatus 500according to embodiment 4 of the present invention can reproduceinformation recorded in the multi-layered information recording medium50 having two recording layers to which defect management of the presentinvention is applied. The reproduction operation of user data which isperformed after the focal point of the laser light 536 has been moved toa recording layer to be accessed, is basically the same as thereproduction operation of user data performed for a single-layeredinformation recording medium. Thus, it is clearly appreciated that anyuser data reproduction procedure for an informationrecording/reproducing apparatus designed for a single-layered disc canbe used.

FIG. 22 is a flow chart for illustrating a procedure of updating defectmanagement information according to embodiment 4 of the presentinvention. In this embodiment, assume that a formatting process for themulti-layered information recording medium 50 includes an initializationprocess for defect management information and a process of increasingthe size of a spare area.

At the first step of this updating process, i.e., at step 901, the CPU514 determines whether or not a necessary formatting process is aprocess of increasing the size of a spare area. If so, the processproceeds to step 902; if not, the process proceeds to step 903.

At step 902, the CPU 514 sets a value of the end spare area size 205 ofthe DDS 20 (FIG. 7).

At step 903, the CPU 514 sets the respective values of the DDS 20 topredetermined values of the device, and sets the DL entry number 302 ofthe DL 21 to 0.

At step 904, the CPU 514 determines whether or not the focal point ofthe laser light 536 is following a track of a reference layer. If so,the process proceeds to step 906; if not, the process proceeds to step905.

At step 905, the CPU 514 instructs the servo circuit 509 to let thefocal point of the laser light 536 to follow the track of the referencelayer.

At step 906, the optical head section 535 records defect managementinformation, including the DDS 20 and DL 21, in a sector included in thedefect management region 12.

FIG. 23 is a flowchart 1000 for illustrating a recording procedure insectors according to embodiment 4 of the present invention, whereinreplacement is considered.

At the first step of this recording process, i.e., at step 1001, the CPU514 converts the LSNs to the PSNs according to the procedure shown inFIG. 21.

At step 1002, the CPU 514 refers to the layer number of the PSN todetermine whether or not a recording layer in which the focal point ofthe laser light 536 exists is identical to a recording layer in whichinformation is to be recorded. If identical, the process proceeds tostep 1004; if not, the process proceeds to step 1003.

At step 1003, the CPU 514 instructs the servo circuit 509 to let thefocal point of the laser light 536 to follow a track of the recordinglayer in which information is to be recorded.

At step 1004, information is recorded in a sector indicated by the PSNobtained at conversion step 1001.

At step 1005, the CPU 514 controls the optical head section 535 toreproduce the information recorded in the sector, thereby determiningwhether or not recording of the information in the sector was successful(i.e., whether or not a defect sector exists in the user data area 5).If successful, the recording process ends; if not, the process proceedsto step 1006.

At step 1006, the CPU 514 assigns a spare sector to a defect sector,thereby replacing the defect sector with the spare sector (details ofthe process of assigning a spare sector will be described later withreference to FIGS. 24A and 24B).

At step 1007, it is determined whether or not the process of replacingthe defect sector with the spare sector was impossible. If impossible,the recording process ends; if possible, the process returns to step1001.

FIG. 24A is a flowchart for illustrating an assignment procedure ofspare sectors according to embodiment 4 of the present invention.

The process of assigning spare sectors includes a process of finding atleast one available spare area among a plurality of spare areas includedin the multi-layered information recording medium 50, and a process ofselecting, from the found at least one available spare area, a sparearea which is closest to a defect sector. The details of the process ofassigning spare sectors are described below with reference to FIG. 24A.

At the first step of the spare sector assignment process, i.e., at step1101, the CPU 514 refers to the spare full flag group 208 (FIG. 8) todetermine whether or not the multi-layered information recording medium50 has an available spare area. If there is no available spare area, theCPU 514 determines that the assignment process is impossible andaccordingly terminates the assignment process. If there is an availablespare area, the process proceeds to step 1102.

At step 1102, the CPU 514 determines whether the radial position of adefect sector is closer to a spare area at the inner circumference sideor closer to a spare area at the outer circumference side. If the radialposition of the defect sector is closer to a spare area at the innercircumference side, the process proceeds to step 1103. If the radialposition of the defect sector is closer to a spare area at the outercircumference side, the process proceeds to step 1104.

At step 1103, the CPU 514 refers to the spare full flag group 208 todetermine whether or not the spare area at the inner circumference sideis available. If available, the process proceeds to step 1105; if not,the process proceeds to step 1106.

At step 1104, the CPU 514 refers to the spare full flag group 208 todetermine whether or not the spare area at the outer circumference sideis available. If available, the process proceeds to step 1106; if not,the process proceeds to step 1105.

At step 1105, the CPU 514 refers to the spare full flag group 208 todetermine whether or not a spare area which is in a recording layerwhere the defect sector exists, and which is at the inner circumferenceside, is available. If available, the process proceeds to step 1107; ifnot, the process proceeds to step 1108.

At step 1106, the CPU 514 refers to the spare full flag group 208 todetermine whether or not a spare area which is in a recording layerwhere the defect sector exists, and which is at the outer circumferenceside, is available. If available, the process proceeds to step 1109; ifnot, the process proceeds to step 1110.

At step 1107, the CPU 514 assigns a spare sector included in the sparearea which is in a recording layer where the defect sector exists, andwhich is at the inner circumference side, to the defect sector.

At step 1108, the CPU 514 assigns a spare sector included in a sparearea which is in a recording layer different from the recording layerwhere the defect sector exists, and which is at the inner circumferenceside, to the defect sector.

At step 1109, the CPU 514 assigns a spare sector included in a sparearea which is in a recording layer where the defect sector exists, andwhich is at the outer circumference side, to the defect sector.

At step 1110, the CPU 514 assigns a spare sector included in a sparearea which is in a recording layer different from the recording layerwhere the defect sector exists, and which is at the outer circumferenceside, to the defect sector.

In the spare sector assignment procedure shown in FIG. 24A, a sparesector included in a spare area, whose radial distance from the defectsector is shortest, is used as a spare sector. If the radial distance isshorter, the time required for a seek operation, which is accompanied bya movement of the transport table 507, becomes shorter. According to thepresent invention, a different assignment procedure may be used so longas an objective of the present invention, i.e., using a spare sectorwhose radial distance from a defect sector is shortest as a sparesector, is attained.

FIG. 24B shows a flowchart 1120 which illustrates an alternative sparesector assignment process according to embodiment 4 of the presentinvention.

This alternative assignment process includes the following processes: aprocess of finding at least one available spare area among a pluralityof spare areas included in the multi-layered information recordingmedium 50; a process of determining whether or not at least one of thefound available spare areas exists in a recording layer where a portionof the user data area 5 including a defect sector exists; and a processof selecting a spare area which is closest to the defect sector from theat least one found available spare area if it is determined that none ofthe at least one found spare area exists in the recording layer wherethe defect sector exists. The details of the process of assigning sparesectors are described below with reference to FIG. 24B.

At the first step of the spare sector assignment process, i.e., at step1121, the CPU 514 refers to the spare full flag group 208 to determinewhether or not the multi-layered information recording medium 50 has anavailable spare area. If there is no available spare area, the CPU 514determines that the assignment process is impossible and accordinglyterminates the assignment process. If there is an available spare area,the process proceeds to step 1122.

At step 1122, the CPU 514 refers to the spare full flag group 208 todetermine whether or not a spare area included in a recording layer inwhich a defect sector exists is available. If available, the processproceeds to step 1123; if not, the process proceeds to step 1124.

At step 1123, the CPU 514 determines whether the radial position of adefect sector is closer to a spare area at the inner circumference sideor closer to a spare area at the outer circumference side. If the radialposition of the defect sector is closer to a spare area at the innercircumference side, the process proceeds to step 1125. If the radialposition of the defect sector is closer to a spare area at the outercircumference side, the process proceeds to step 1127.

At step 1125, the CPU 514 refers to the spare full flag group 208 todetermine whether or not a spare area residing at the innercircumference side of that recording layer is available. If available,the process proceeds to step 1129: if not, the process proceeds to step1131.

At step 1127, the CPU 514 refers to the spare full flag group 208 todetermine whether or not a spare area residing at the outercircumference side of that recording layer is available. If available,the process proceeds to step 1131: if not, the process proceeds to step1129.

The processes of steps 1124, 1126, and 1128 are the same as those ofsteps 1123, 1125, and 1127, respectively, except that a recording layerincluding a spare area which is to be used is different from a recordinglayer including the defect sector.

At step 1129, the CPU 514 assigns a spare sector included in the sparearea which is in a recording layer where the defect sector exists, andwhich is at the inner circumference side, to the defect sector.

At step 1130, the CPU 514 assigns a spare sector included in a sparearea which is in a recording layer different from the recording layerwhere the defect sector exists, and which is at the inner circumferenceside, to the defect sector.

At step 1131, the CPU 514 assigns a spare sector included in a sparearea which is in a recording layer where the defect sector exists, andwhich is at the outer circumference side, to the defect sector.

At step 1132, the CPU 514 assigns a spare sector included in a sparearea which is in a recording layer different from the recording layerwhere the defect sector exists, and which is at the outer circumferenceside, to the defect sector.

The spare sector assignment procedure shown in FIG. 24B uses a sparesector in a spare area included in a recording layer in which a defectsector exists so long as such a spare sector is available. By using sucha spare sector included in a recording layer in which a defect sectorexists, it is not necessary to change different recording parameters forrespective recording layers. For example, if in an information recordingoperation in a recording layer, the recording power is not optimallycalibrated for the other recording layers, the assignment procedureshown in FIG. 24B can be performed faster than the assignment procedureshown in FIG. 24A. According to the present invention, a differentassignment procedure may be used so long as an objective of the presentinvention, i.e., using a spare sector in a spare area included in arecording layer in which a defect sector exists so long as such a sparesector is available, is attained.

As described above, the information recording/reproducing apparatus 500according to embodiment 4 of the present invention can recordinformation in the multi-layered information recording medium 50 havingtwo recording layers to which defect management of the present inventionis applied. The information recording/reproducing apparatus 500 canassign a spare sector selected from a spare area included in a recordinglayer which is different from a recording layer in which a defect sectorexists. The information recording/reproducing apparatus 500 can performa process of assigning a spare sector while giving a greater weight toreduction of the seek time as described above with reference to FIG.24A. Further, the information recording/reproducing apparatus 500 canperform a process of assigning a spare sector while giving a greaterweight to reduction of the time required for setting the recording poweras described above with reference to FIG. 24B. Herein, an operationperformed after an optical head section reaches a recording layer to beaccessed is basically the same as that performed on a single-layeredinformation recording medium. Thus, it is clearly appreciated that anyrecording procedure arranged for an information recording/reproducingapparatus designed for a single-layered information recording medium canbe used.

The recording operation in the user data area which is performed afterthe focal point of the laser light 536 has been moved to a recordinglayer to be accessed, is basically the same as the recording operationof user data performed for a single-layered information recordingmedium. Thus, it is clearly appreciated that any user data recordingprocedure for recording in a user data area, which is adapted for aninformation recording/reproducing apparatus designed for asingle-layered disc, can be used.

Although the multi-layered information recording medium 50 described inembodiment 1 was used to explain embodiment 4 of the present invention,it is clearly appreciated that the multi-layered information recordingmedium 60 described in embodiment 3 can also be used. Further, it isalso clearly appreciated that the multi-layered information recordingmedium 56 described in embodiment 2 can also be used when the conversionprocessing at step 801 shown in FIG. 21 is applied to three or morerecording layers.

Although in the above descriptions of the present invention,reproduction/recording of information and defect management areperformed on the units of a sector, it is clearly appreciated that thepresent invention is applicable even when reproduction/recording ofinformation and defect management is performed on the units of a blockwhich includes a plurality of sectors, or on the units of an ECC blockwhich is, for example, a unit based on which an error correction code ofa DVD disc is calculated. For example, in the case where the aboveoperations are performed on the units of an ECC block, a plurality ofsectors included in the ECC block in which a defect sector exists arereplaced with a plurality of spare sectors, whereby the defect sector isreplaced with a spare sector. Such a modified embodiment is made withinthe spirit and applicable range of the present invention, and anymodified embodiment which is readily appreciated by those skilled in theart, falls within the scope of the claims of the present invention.

According to a multi-layered information recording medium of the presentinvention, one recording layer includes defect management informationfor all the recording layers. With such an arrangement, the defectmanagement information for all the recording layers can be obtained bysimply accessing the one recording layer. Thus, continuous accessibilitycan be improved.

According to a multi-layered information recording medium of the presentinvention, a first spare area which is positioned so as to be contiguousto a first user data area and a second spare area which is positioned soas to be contiguous to a second user data area are placed approximatelyat the same radial position on the multi-layered information recordingmedium. With this arrangement, when the focal position of laser lighttransits from the first user data area to the second user data area, themoving distance of an optical head section along the radial direction isideally zero (0). Thus, continuous accessibility can be improved.

According to a multi-layered information recording medium of the presentinvention, a detected defect sector can be replaced with a spare area ofany recording layer. Thus, spare areas can be efficiently used, andreliability of data can be improved.

According to a multi-layered information recording medium of the presentinvention, when the number of defect sectors is greater than what isexpected, the defect sectors can be replaced with spare sectors byincreasing the size of a spare area. Thus, reliability of data can beimproved.

According to a multi-layered information recording medium of the presentinvention, consecutive numbers are assigned as LSNs to the user dataareas throughout all the recording layers. With such an arrangement, acommon defect management method can be applied to both a multi-layeredinformation recording medium wherein the recording/reproductiondirection is the same in all of the recording layers and a multi-layeredinformation recording medium wherein the recording/reproductiondirection is alternately inverted for the respective recording layers.Thus, the cost of production and development of the multi-layeredinformation recording medium can be reduced.

According to a multi-layered information recording medium of the presentinvention, control information regions such as a region for storingrecording/reproduction parameters, a region for storing defectmanagement information, or the like, are provided in one recordinglayer. With such an arrangement, the control information for all therecording layers can be obtained by simply accessing the one recordinglayer. Thus, continuous accessibility can be improved.

According to a multi-layered information recording medium of the presentinvention, control information regions are provided in a referencelayer. Thus, recording/reproduction operations can be performed instrict conformity with the information in the control informationregions.

According to a multi-layered information recording medium of the presentinvention, every recording layer has its OPC region for calibrating therecording power. With such an arrangement, the recording power can beoptimally calibrated for each recording layer.

According to an information reproduction method and informationreproduction apparatus of the present invention, information can bereproduced from a multi-layered information recording medium whichincludes defect management information about a plurality of recordinglayers.

According to an information recording method and information recordingapparatus of the present invention, information can be recorded in amulti-layered information recording medium which includes defectmanagement information about a plurality of recording layers.

According to an information recording method and information recordingapparatus of the present invention, a defect sector is replaced with aspare sector included in a spare area which is closer to the defectsector. With such an arrangement, assignment of a spare sector can beperformed while giving a greater weight to reduction of the timerequired for seeking along the radial direction.

According to an information recording method and information recordingapparatus of the present invention, a defect sector is replaced with aspare sector included in a spare area residing in a recording layer inwhich the defect sector exists. With such an arrangement, assignment ofa spare sector can be performed while giving a greater weight toreduction of the time required for setting the recording power.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

1. A multi-layered information recording medium including a plurality ofrecording layers, the multi-layered information recording mediumcomprising: a user data area for recording user data; a plurality ofspare areas including at least one replacement region, wherein when theuser data area includes at least one defect region, the at least onereplacement region may be used in place of the at least one defectregion; and a plurality of defect management areas including a pluralityof defect lists which are information to manage at least one defectregion of the user data area, wherein the plurality of recording layersinclude a first recording layer and a second recording layer positionedcontiguous to each other, the first recording layer includes a firstuser data area which is a portion of the user data area, and a firstspare area which is one of the plurality of spare areas, the secondrecording layer includes a second user data area which is anotherportion of the user data area, and a second spare area which is anotherone of the plurality of spare areas, the first spare area is positionedso as to be contiguous to the first user data area, the second sparearea is positioned so as to be contiguous to the second user data area,the first spare area and the second spare area are positionedapproximately at the same radial position on the multi-layeredinformation recording medium, and each of the plurality of defect listsincludes information about a defect sector position and a replacementsector position.